The invention relates generally to the field of semiconductor technology and in particular to a method for etching metal with high accuracy.
The increasing need for communications has been a consistent driver for expanding the spectrum utilized for wireless communications. In recent years frequencies in excess of 10 GHz have become commonplace in satellite video and data transmission, while frequencies up to 3 GHz are common in cellular communications. In general, components designed for such high frequencies are also known as radio frequency (RF) components. The generation and detection of RF requires precision passive electronic components, such as capacitors, inductors and resonant filters. Unfortunately, precision passive electronic components are typically expensive and as such prevent the rapid spread of technology based on these frequencies.
Semiconductor manufacturing technology is well developed, and is an excellent technology for reducing the cost of devices and components, while maintaining a high level of precision and repeatability. Many prior art techniques exist for manufacturing capacitors, unfortunately the need for high precision as required for RF applications, and low cost has not been met. In particular a number of barriers to precision control include diffusion of any deposited metal, lack of adhesion of a deposited metal to a dielectric and precision control of the height of a dielectric.
In certain precision RF passive components there is a need to produce metal lines of 6-25 microns is width with an accuracy of plus or minus 0.5 micron. Preferably the metal comprises copper. An accuracy of greater than 10% is difficult to achieve with prior art equipment.
Thus, there is a need for a method for producing a precision RF passive component, allowing accuracy greater than 10% and suitable for use with a metal such as copper.